


you make me weak

by mitigates



Series: Discord Prompts [2]
Category: Haikyuu!!
Genre: Aged-Up Character(s), F/M, Friends With Benefits, Genderbending, M/M, Mostly porn, Multiple Orgasms, Oikawa wakes up as a girl, Plot What Plot/Porn Without Plot, Porn with Feelings, Vaginal Sex, no beta we die like daichi, that's it that's the fic, they have sex, this is just sex
Language: English
Status: Completed
Published: 2021-03-06
Updated: 2021-03-06
Packaged: 2021-03-19 11:26:13
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,284
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/29873928
Author URL: https://archiveofourown.org/users/mitigates/pseuds/mitigates
Summary: Iwaizumi slowly sat up and leaned forward. She looked like his sister, but younger. Same hazelnut pools of brown for eyes, same hair but longer. Iwaizumi’s face reddened as his eyes travelled down the rest of her body, the tank top Oikawa had gone to sleep in was stretched across her chest. The boxers were riding up her thighs.OrOikawa wakes up as a girl. They immediately have sex.
Relationships: Iwaizumi Hajime/Oikawa Tooru
Series: Discord Prompts [2]
Series URL: https://archiveofourown.org/series/2198040
Comments: 2
Kudos: 71





	you make me weak

**Author's Note:**

> \- discord challenge: genderbending characters -

It was a normal day, a day like any other. Oikawa woke up slowly, his eyelids fluttering open as the sun assaulted his vision. He sat up and yawned. He wasn’t feeling that great though, his chest felt heavier than normal. He blinked away the sleepiness threatening to overtake his body again. He swung his legs over the bed and moved his foot around for his slippers. He had slept at Iwa-chan’s last night and was trying to be at least a little bit careful about waking his best friend up.

_ Weird _ . Oikawa thought to himself as he had to stretch a little farther than normal to stuff his foot into his slipper. He looked down and tried to remember when he had gotten a french pedicure. He wiggled his toes to make sure they were really his and sure enough, they moved. Oikawa’s eyes widened as they traveled up his smooth bare leg, free of the thin hairs he had grown accustomed to that sprouted when he was a teenager. Oikawa reached back to shake Iwaizumi as he finally saw why his chest felt so heavy. He wasn’t sick. He had boobs.

Oikawa shrieked and was immediately hit in the face with a pillow. Oikawa continued his panicking as Iwaizumi rolled toward him. Oikawa shrieked again as Iwaizumi tried to muffle the cacophonous noises escaping his mouth. “Shittykawa, shut the fuck up!” Iwaizumi punctuated each work with a push of the pillow.

Iwaizumi sat up suddenly when he realized the body beneath him was much smaller than he was used to abusing. He slowly lifted the pillow and stared down at a pair of painfully familiar brown eyes on a face he kind of recognized, surrounded by a halo of chestnut hair he definitely recognized. 

Iwaizumi blinked slowly, now straddling the girl beneath him, and fell backwards. 

“Iwa-chan!”

“Iwa-the fuck? Who the fuck are you?” Iwaizumi laid back on the large bed as he kicked away from the strange girl who was now sobbing dramatically.

“I-Iwa-ch-chan! It’s me!” She sputtered, rubbing his eyes with both fists.

Iwaizumi snorted as he watched not-Oikawa do something Oikawa would do. “I’m sorry- what?”

She managed a glare only a woman could produce and Iwaizumi froze. “It’s me! It’s Oikawa!”

Iwaizumi slowly sat up and leaned forward. She looked like his sister, but younger. Same hazelnut pools of brown for eyes, same hair but longer. Iwaizumi’s face reddened as his eyes travelled down the rest of her body, the tank top Oikawa had gone to sleep in was stretched across her chest. The boxers were riding up her thighs.

Oikawa caught his gaze and swatted the side of his head. “Iwa-chan! Control yourself!”

“You’re- no- you're not- Oikawa?” Iwaizumi squeaked the words out as Oikawa rolled his- wait, her eyes?

“Help me!” Oikawa whined.

Nobody could whine like Oikawa either. Iwaizumi snorted again. “Of course as a girl you’re still annoying.”

“Fuck you!”

“I can see your nipples.” Iwaizumi pointed out with a lewd wink.

Oikawa squawked and covered her chest. “Pervert!”

“So, this is a dream or a curse. Which is it?”

“I haven’t done anything indecent lately, so it must be a dream.” Oikawa included.

“You saying that you haven’t done anything indecent is indecent, assikawa.” Iwaizumi reached out and tugged on a strand of her hair. “Cute.”

Oikawa blushed, the swells of her cheeks turning bright red. “Iwa-chan- wait, you think I’m cute?”

Iwaizumi shrugged. “I think girls are cute.”

Oikawa glared at him. “You do?”

Iwaizumi rolled his eyes. “You’re cute as a girl.”

Oikawa seemed to ponder that for a moment. She tilted her head slightly, exposing her neck as her hair fell over her shoulder. She brought a leg up to her chest and wrapped a long pale arm around it. Her deep brown hair spilled over and Iwaizumi was tracking every movement. His eyes were narrowed when the oversized shirt that was falling off of Oikawa’s undersized shoulder.

“Fuck.”

Oikawa’s eyebrows raised and Iwaizumi flushed as he realized he uttered the words out loud. Oikawa and Iwaizumi had been having an on-again/off-again relationship since they were in high school. They never went and explicitly stated that they were in a relationship but the amount of kisses, orgasms, and late night phone calls shared between the two of them suggested something different. Now, with Iwaizumi struggling to keep still while Oikawa had seemingly changed into a girl overnight, he still found himself wildly attracted to his best friend. 

“Iwa-chan-” Oikawa whispered the words as Iwaizumi flung himself across the bed, pressing a rough kiss against Oikawa’s lips.

“Have you ever-”

“With a girl?”

“Yeah-”

“Uh- no- it’s not- it’s not-” Iwaizumi’s response came out quieted and stuttered as they kissed. 

Oikawa’s lips were as soft as they ever were, perfectly melding with Iwaizumi’s rougher ones. He was reminded of their first kiss. It was unexpected when they each turned in opposite directions at the same time and their lips barely brushed. Oikawa’s eyes were wide and glassy. Iwaizumi dove right in and their teeth clacked but they kept going. 

Just like that moment, they kept going, albeit slightly more confidently. 

Oikawa whimpered as Iwaizumi grinded against her. “Iwa-chan,” Oikawa scratched her longer nails down Iwaizumi’s back, appreciating the man's thick frame from an entirely new perspective. “God- you’re so-”

Iwaizumi sucked on her neck and she groaned, asking for more. Iwaizumi smirked against her skin and slid his hand down her torso, pushing it up and underneath her shirt. She arched against his hand as he lifted the soft cotton. Iwaizumi sat up slightly and pressed a kiss to her navel. Oikawa let out a whine as Iwaizumi’s thumbs hooked on the edge of her boxers.

Iwaizumi hesitated for a moment and looked up at Oikawa’s flushed face. Oikawa raised an arched eyebrow at him. 

“What?”

“I- I’ve never-  _ you know _ .” Iwaizumi kissed her stomach lightly and smirked as Oikawa shuddered.

“Well I haven’t exactly done this either, Iwa-chan! I’ve never even- I- I mean I doubt it’s  _ that _ different.” 

Iwaizumi snorted. “I’ve taken enough sex ed to know that it’s going to be different especially since this is technically your first time.” His last few words were teasing and Oikawa started sputtering.

“I’m- what? The fuck! Hajime, I’m not a  _ virgin _ !” Oikawa whispered-screamed at his bulky best friend. She sat up and nearly knocked into his head as she lunged forward. 

Iwaizumi fell onto his back from sheer surprise. He stretched out and gripped Oikawa’s hips as she settled on top of him. Her legs were stretched wide to accommodate Iwaizumi’s much larger frame. She glared down at him as he smirked up at her. Oikawa huffed out a laugh and reached down to tug on the hem of her shirt.

“Hmm, Iwa-chan, it’s a little hot, yeah?” Oikawa bit back a laugh at the thunderbolt of surprise that crossed Iwaizumi’s face. She removed her shirt slowly, teasing it up her torso. She tossed it off of the bed and pressed her palms against Iwaizumi’s heaving chest. “Yeah?”

Iwaizumi’s hands slid up her hips, pressing against the lithe body he had grown so accustomed to but was now completely unfamiliar with. Oikawa’s features had softened: the corners of her eyes weren’t as sharp, her lips were more plump and smoother, her chest was- her chest was full and soft and so warm-

Oikawa arched her back when Iwaizumi’s fingers lightly pinched her nipple. She exhaled heavily and rolled her hips as Iwaizumi brought his other hand up. He remembered that other Oikawa liked having his nipples played with as well. It seemed to be no different as he rolled the pink nub between his fingers. 

Oikawa, ever flexible, managed to slide her boxers off without moving much. Iwaizumi simply stared and adjusted underneath her, painfully hard. 

“Fuck, Oikawa.”

Oikawa bit her lip and rolled her hips against, closing her eyes at the delicious friction between her legs. Iwaizumi rose and gripped her hips, flipping her onto her back. She yelped as her back hit the mattress and Iwaizumi’s mouth swallowed the sound. He leaned back for a moment and tugged his own shirt off. He stopped before pressing back against her, taking a second to admire her body. Iwaizumi had always loved Oikawa’s body. Other Oikawa was long and lean and strong and soft, he loved taking the time to worship it with his mouth.

Iwaizumi pressed his lips to her neck and reached into his nightstand as he kicked his boxers off.

Oikawa slid her thighs up against his and hooked her ankles behind Iwaizumi’s back. “I don’t- I don’t think you’ll need- the uh, the lube.”

Iwaizumi dropped the bottle onto the floor at Oikawa’s words, his hand shaking more than he would care to admit. “Oh um, right.” He turned back to Oikawa and set the condom beside them. He trailed a hand down Oikawa’s body and slipped it between her legs. 

“Hah-Ha-Hajime~” Oikawa sighed blissfully, closing her eyes. 

Iwaizumi’s pulled every bit of knowledge about the female anatomy that he had read in textbooks and see in the occasional hetero porn that he watched in high school. The pad of his thumb found her clit easily, he pressed and rubbed a small circle. 

Oikawa’s back bowed toward his hand as he groaned loudly. Iwaizumi sucked her bottom lip between his teeth and bit down as he applied more pressure. How different was it from when he pressed against Oikawa’s prostate? Not much, he guessed. Except it took significantly less time before Oikawa was gasping beneath him, whimpering and writhing. 

Oikawa opened her eyes, her pupils so dilated that her eyes appeared to be dark pools of ink. “What the  _ fuck _ ?”

Iwaizumi smirked and kissed her, sliding his tongue against Oikawa’s teeth. “That was fast.”

“Fuck- do it again!” Oikawa pushed her hips against Iwaizumi, angling her body until she felt Iwaizumi’s wet cock slide between her legs. “C’mon Hajime, fuck me already.”

The sweet whisper of words was too much for the man to handle. He grunted and ripped the foil packet open with his teeth. He looked up at Oikawa and pushed her hair back from where it had stuck to the sweat on her forehead. Her chest was flushed from the fresh orgasm and she had a light sheen that spread across her body. 

“What’s wrong?” Oikawa asked, voice smaller than Iwaizumi had ever heard it.

“I love you.”

Iwaizumi didn’t give Oikawa a chance to process or respond to the confession as he pushed inside of her. Oikawa’s high-pitched moan filled the room as she tightened her legs around his waist. Iwaizumi waited another moment for her to adjust to being filled, but only a moment. He pressed a sloppy impatient kiss to her mouth, keeping one hand on her forehead as he pushed her hair back. He thrust slowly, he pushed deep inside of her until his hips pressed against her thighs. He moved faster, frantic almost, as if the thought of not being pressed flush against her would draw him mad. 

“Tooru~” Her name is a gasp from his lips, a ragged exhale from his lungs and mouth, groaned against Oikawa’s warmed cheek. There’s a burning sense of desire behind Iwaizumi’s movements. He sinks his teeth into her shoulder, sucking her skin hungirly. 

Oikawa traced Iwaizumi’s taut skin with her fingertips, a groan stuck in her throat. She traced the curves and dips of his shoulders, his chest, his stomach. Iwaizumi kissed her jaw and moved a hand back down to her chest, his thumb grazing her nipple. She cried out at a particularly harsh snap of his hips, driving into her over and over with long strokes. They’re both burning up as their bodies slide together.

“Hajime-” Oikawa gasped his name.

Iwaizumi’s lips stretched into a smirk against her neck. “Mmh, yes, Tooru?” He raised his head and met her stare, not wanting to admit how hard it was to hold her stare. 

“M-more- Please. Pleasepleaseplease~” Oikawa whimpered and sobbed, her body shaking uncontrollably. 

Iwaizumi obliged, kissing her one more time before pulling out of her and slamming back in. A few more movements was all it took for either of them to come, bursting into a thousand tiny pieces. 

Iwaizumi’s arms were shaking as he held himself up by his elbows, his chest rising as he strained to stay still and not smother her smaller body. Oikawa attempted to slow down her frantically beating heart as she steadied her breathing. Iwaizumi slowly slid out of her and rolled onto his side, pulling her against his chest. She flung her arm across his broad body and breathed against his torso. Her eyes closed as she felt Iwaizumi carding his fingers through her hair. She let sleep take her.

~+~+~+~

When Oikawa awoke again, he felt warmer than he had ever felt before. He slowly opened his eyes and realized he was still surrounded by Iwaizumi. The back of his neck didn’t itch any longer and he peered between them. He was himself again. 

He tilted his head up and watched Iwaizumi sleep. The hard lines of his face were less sharp when he was dozing. Oikawa kissed his chin lightly, sighing against the stubble that had grown overnight. The corner of his mouth quirked up slightly, the smallest of sleepy smiles.

“Tooru,” Iwaizumi whispered his name.

Oikawa held his palm over Iwaizumi’s eyes. “Wait-, waitwait- don’t- don’t open your eyes yet.” He swallowed thickly and cleared his throat. “I love you too. I hope you’ll still-”

Iwaizumi grunted and pushed himself forward, latching onto Oikawa’s mouth again. “Shut up, shittykawa.”

**Author's Note:**

> i was about to throw in a 'wrong hole' joke here but i stopped myself. be proud of me, please.


End file.
